Re: too long mac address for --mac-source netfilter option

[Stefan Smietanowski]

Hi!
> I am trying to use the --mac-source option in the netfilter code to better refine access to my linux box. However, I > have run up against something. The router through which my private subnet work box passes sends a 14-group "invalid" > mac address, presumably as an attempt to conceal the real hextile mac address. However, the code for the > --mac-source netfilter option is looking for a valid hextile mac address and complains loudly as such (numerals converted to x's):
> 
> iptables v1.1.1: Bad mac address `xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx'
> 
> to the respective iptable line:
> 
> $IPT -A INPUT -p tcp -s xxx.xxx.xxx.xxx -d $NET -m mac --mac-source xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx --dport 5900:5901 -j ACCEPT
> 
> The idea here is to allow VNC access to my home box with the access filtered by both IP and mac address.
> 
> Is there a resolution to this other than a rewrite and recompile of the relevant sections of the iptable code? Or am I stuck? I know this option is tagged by Rusty as experimental still so I would assume that the code is open for feedback ;) The question could be rephrased as: is there any chance of allowing "invalid" mac addresses to be recognized by the --mac-source option of the netfilter code? Running Redhat v7/kernel 2.4.1-ac15.

Umm..  An ethernet MAC address is 48bit long, ie AA:BB:CC:DD:EE:FF, 6
groups, not 14. Is this really an ethernet
interface? (If it really has 14 groups).

// Stefan